USA Today Bestselling author of 35 books, including the Witness series and the new Finn O’Brien series.
This sounds like an exciting and intricate project. It also sounds like you need to stop and assess your critique group’s input. Having not seen the work it’s hard to make a judgment regarding your question, but I think the changing voices would be necessary for a project of this scope. So ask yourself if, in this instance, is your author’s instinct appropriate or your critique group’s caution?
I wrote a book called Before Her Eyes that had first person and third person parallel stories. The voices had to be different and I wrote them as such. Readers had no problem with this.
What I do question, however, is the suggestion that you have three main characters. I will accept they are the MC’s of their separate sections of the book. However (again an assumption) they will all come together at some point. There will have to be a conclusion to this book and that means one character will have the star turn.
I would be curious to know if you really have three MCs or one MC and some very, very strong supporting characters. I will refer back to Before Her Eyes. While each track had a main character the climax of the book showcased one. His journey overrode hers. Good luck.